SINGLE CHIP MICROCOMPUTER

摘要

PROBLEM TO BE SOLVED: To enlarge the application range of a single chip microcomputer provided with the extension access function of an external address space and program protection. SOLUTION: This microprocessor is provided with an area specifying means 15 for dividing the address space of a ROM 13 for storing instructions and data into an instruction area and a data area and outputting area specifying signals SP for specifying the instruction area and the area specifying signals SX for specifying the area of the entire address space of the ROM 13 corresponding to the address output of a CPU 11 and a ROM output control part 14 for outputting the instruction to an internal bus DB by control corresponding to the instruction fetching signals IF of the CPU 11 and the signals SP for specifying the instruction area and outputting the data to the internal bus DB by the control corresponding to the signals for specifying the data area obtained by the signals SP and SX.